Stephen S. Chang

Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States

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Publications (47)88.68 Total impact

    Journal of Food Science 08/2006; 38(3):393 - 397. DOI:10.1111/j.1365-2621.1973.tb01438.x
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    ABSTRACT: The presence of antioxidants in spices, specifically Rosemary and sage, is well known. However, the extracts of such spices usually have a strong odor and bitter taste and therefore cannot be used in most food products. This paper reports a patented process for the extraction of Rosemary and sage followed by a vacuum steam distillation of the extract in an edible oil or fat to obtain a bland natural antioxidant. Fractionation and characterization of the active antioxidant ingredient in the extract of Rosemary and sage is also reported.
    Journal of Food Science 08/2006; 42(4):1102 - 1106. DOI:10.1111/j.1365-2621.1977.tb12676.x
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    ABSTRACT: Techniques involved in the study of volatile flavor compounds of cooked meat, including isolation of the volatile flavor compounds, fractionation of the isolated volatiles by gas chromatography and identification of the pure gas chromatographic fractions by infrared and mass spectrometry are reviewed. The volatile compounds identified to date, as components of cooked meat, such as boiled beef and roast beef, are reported. The importance of heterocyclic compounds containing oxygen, nitrogen and sulfur in the ring and pyrazine compounds to the flavor of meat are discussed with their possible mechanisms of formation. The possible use of high pressure liquid chromatography for the fractionation of the less volatile flavor compounds in cooked meat and the many difficulties of this technique are reviewed. The deterioration of flavor during storage and processing as caused by the qualitative and quantitative changes of flavor compounds are discussed with detailed information on the change of flavor compounds during the retorting of beef stew.
    Journal of Food Science 08/2006; 42(2):298 - 305. DOI:10.1111/j.1365-2621.1977.tb01486.x
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    ABSTRACT: SUMMARY— 2-Pentyl furan is identified as a component of the volatile decomposition products of slightly autoxidized soybean and cottonseed oils and those of thermal oxidation of corn oil and hydrogenated cottonseed oil. The flavor threshold of this compound in oil at room temperature is 1 ppm. At concentrations of 1-10 ppm, it imparts to the oil a characteristic beany odor and flavor reminiscent of those of a reverted soybean oil. Expert organoleptic panels consistently identified a deodorized cottonseed oil containing 5 ppm of 2.pentyl furan as a reverted soybean oil. It is proposed that this compound is formed by autoxidation of linoleic acid.
    Journal of Food Science 08/2006; 32(4):372 - 374. DOI:10.1111/j.1365-2621.1967.tb09687.x
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    ABSTRACT: Seven unsaturated lactones, viz., the lactones of 4-hydroxy-nonenoic acid, with the double bond at the 2 and 3 position, respectively, 4-hydroxy-octenoic acid with the double bond at the 2 and 3 position, respectively, 5-hydroxy-4-nonenoic acid, 5-hydroxy-2-octenoic acid, and 5-hydroxy-2-undecenoic acid, were synthesized. Their chemical structures were confirmed by their infrared and mass spectra. Organoleptic evaluation indicated that -lactones with unsaturation at the 2 or 3 positions imparted a characteristic deep-fat fried flavor to cottonseed oil when added at 2.5 ppm. Furthermore, -lactones with unsaturation at the 3 position could improve the flavor of margarine and snack foods.
    Journal of Food Science 08/2006; 43(4):1248 - 1252. DOI:10.1111/j.1365-2621.1978.tb15280.x
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    ABSTRACT: Volatile flavor compounds were isolated from 190 lb of roasted eye round beef. The neutral fraction of the flavor isolate was subjected to extensive gas chromatographic fractionation and the pure fractions obtained were identified by GC-mass spectrometry. A total of 67 compounds were reported to be new constituents in beef flavor.
    Journal of Food Science 08/2006; 47(6):2068 - 2069. DOI:10.1111/j.1365-2621.1982.tb12950.x
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    ABSTRACT: The volatile flavor constituents of defatted soy flour were isolated by a specially designed apparatus. The isolated volatiles were fractionated by gas chromatography. The fractions with characteristic beany, grassy, and green odors were identified by infrared and mass spectrometry. A total of 25 compounds was identified, including nine alcohols, six aldehydes, nine ketones, and 2-pentyl furan. Among the identified compounds, 2-pentyl furan and ethyl vinyl ketone are probably the key compounds for the beany and grassy odors of the soy flour. All the compounds identified in this study can be postulated as autoxidative decomposition products of soy lipids. Therefore, the presence of these compounds in soy flour might be due to the incomplete removal of lipids in soy flour.
    Journal of Food Science 08/2006; 47(1):16 - 18. DOI:10.1111/j.1365-2621.1982.tb11016.x
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    ABSTRACT: Previous work provided evidence for the occurrence of new alkyloxazoles and alkylthiazoles in the volatiles of cocoa butter from roasted cocoa beans. The synthesis, mass spectral data and sensory properties of these compounds are reported.
    Journal of Food Science 08/2006; 48(5):1570 - 1571. DOI:10.1111/j.1365-2621.1983.tb03544.x
  • Journal of Food Science 08/2006; 40(5):948 - 954. DOI:10.1111/j.1365-2621.1975.tb02241.x
    Journal of Food Science 08/2006; 38(2):345 - 349. DOI:10.1111/j.1365-2621.1973.tb01423.x
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    ABSTRACT: The volatile flavor compounds of fresh, frozen beef stew were isolated, fractionated and identified by standard methodology. A total of 132 compounds was either positively or tentatively identified. A comparison of the volatile compounds and their relative amounts in the fresh, frozen stew with those previously identified in canned stew demonstrated both qualitative and quantitative differences between the volatiles of the two stews. This difference was due mostly to the greater number and amounts of the oxygen-containing compounds such as alcohols, 2-alkenals, esters, lactones, and ionones found in the fresh, frozen stew as compared with the greater number and amounts of hydrocarbons and nitrogen and/or sulfur-containing heterocycles found in the canned stew.
    Journal of Food Science 08/2006; 47(5):1444 - 1448. DOI:10.1111/j.1365-2621.1982.tb04957.x
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    ABSTRACT: Volatile flavor compounds were isolated from 70 kg of freshly roasted Florida Runner peanuts by a specially designed apparatus. The isolated volatile flavor compounds were subjected to extensive gas chromatographic fractionation and the pure fractions obtained were identified by infrared and mass spectrometry. A total of 131 compounds was identified. The following compounds are reported for the first time as flavor components of roasted peanuts: five lactones, incluing γ-crotolactone, 3-methyl-γ-crotolactone and 5-hydroxy-4-nonenoic acid, lactone; four pyrazines, three pyrroles; three pyridines, 13 sulfides, including three monosulfides, six disulfides and four trisulfides; seven thiazoles, two thiophenes, five furanoids, including 2-methyL3(2H)furanone; five oxazoles, three oxazolines, including 2-methyl-3-oxazoline; 12 hydrocarbons, one alcohol, one ketone, two acids, two esters, 2-acetoxy-2-butene, and maltol.
    Journal of Food Science 08/2006; 47(1):127 - 133. DOI:10.1111/j.1365-2621.1982.tb11043.x
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    ABSTRACT: Volatile compounds that may contribute flavor to a wide variety of foods can be isolated in an apparatus which is described. It utilizes the principle of flash evaporation and vaporization from a continuous thin heated film. Liquid foods, such as fruit juices or beer, need no preparation, but foods such as meat and potato chips are first made into a fine water slurry. Vaporized food constituents and water are recovered by condensation in a series of specially designed cold traps. Features and performance of the apparatus are discussed.
    Journal of Food Science 08/2006; 31(6):937 - 940. DOI:10.1111/j.1365-2621.1966.tb03272.x
  • Journal of Agricultural and Food Chemistry 07/1986; 34(4). DOI:10.1021/jf00070a008
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    ABSTRACT: A total of nine acidic and 83 basic compounds was identified in the roasted and unroasted cocoa butter samples. Forty seven of the compounds identified are being reported for the first time in cocoa. The higher concentration of short chain fatty acids in the unroasted cocoa butter is responsible for its acidic aroma characteristics. The roasted cocoa butter generally contained greater numbers and higher concentrations of compounds whose formations would be favored by thermal processing. These compounds included pyrazines, thiazoles, oxazoles and pyridines. The aromas of many of these compounds are characteristic of the aroma differences between the two cocoa butters and contribute to the cocoa aroma of roasted cocoa butter.
    Journal of Oil & Fat Industries 01/1986; 63(8):1031-1036. DOI:10.1007/BF02673793
  • N. Sotirhos, Chi-Tang Ho, Stephen S. Chang
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    ABSTRACT: A high performance liquid chromatographic (HPLC) method has been developed to analyze oxidative and polymerized decomposition products in commercial vegetable oils and heated fats. The oil was passed through a SEP-PAK where the minor constituents were concentrated. The SEP-PAK was eluted with hexane-ether 1:1 (v/v), and 2-propanol. The first eluate contained unsaponifiables and neutral lipids, and the second eluate contained the more polar oxidative and polymerized decomposition products. The second eluate was analyzed by normal phase HPLC. Five commercial vegetable oils were analyzed, and similarities and differences were observed. Four soybean oil samples from different manufacturers also showed differences. Soybean oil heated at 185°C was collected periodically and analyzed. As the heating time increased, the oxidation and polymerization products also increased. Used frying fat samples from a commercial fried chicken manufacturer were analyzed. The frying oil quality reached an equilibrium during three days of operation, because the oil lost in frying was replenished daily with fresh shortening.HPLC- Analyse von oxidativen und polymerisierten Zersetzungsprodukten in handlesüblichen pflanzlichen Ölen und erhitzten FettenEs wurde eine Hochdruckflüssigchromatographiemethode zur Analyse von oxidativen und polymerisierten Zersetzungsprodukten in handlesüblichen pflanzlichen Ölen und erhitzten Fetten entwickelt. Des Öl wurde durch eine SEP-PAK geleitet, wo die Nebenbestandteile konzentriert wurden. Mit Hexan-Ether 1:1 (v/v) und Propanol-2 wurde die SEP-PAK eluiert. Das erste Eluat enthielt das Unverseifbare und neutrale Lipide, das zweite Eluat die polareren oxidativen und polymerisierten Zersetzungsprodukte. Das zweite Eluat wurde durch normale HPLC analysiert. Es wurden fünf handelsübliche Öle analysiert und Ähnlichkeiten und Abweichungen beobachtet. Vier Sojaölproben von verschiedenen Herstellern zeigten ebenfalls Unterschiede. Auf 185° C erhitztes Sojaöl wurde regelmäßig gesammelt und analysiert. In dem Maße, wie die Erhitzungszeit zunahm, stieg der Gehalt an Oxidations- und Polymerisationsprodukten ebenfalls an. Es wurden auch gebrauchte Bratfettproben eines Herstellers für Brathähnchen untersucht. Die Bratfettqualität erreichte nach dreitägigem Einsatz ein Gleichgewicht, weil der Ölverlust durch das Braten täglich mit frischem Fett aufgefüllt wurde.
    Fett/Lipid 01/1986; 88(2):45-48. DOI:10.1002/lipi.19860880203
  • N. Sotirhos, Chi-Tang Ho, Stephen S. Chang
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    ABSTRACT: An HPLC method was optimized to analyze soybean phospholipids. It uses a silica column with UV detection at 210 nm, and a mobile phase consisting of hexane, isopropanol and water. Separation is achieved by keeping the hexane to isopropanol ratio constant and varying the water concentration in a gradient elution program. Components in the HPLC chromatogram were identified by comparison with retention times of authentic compounds. The method was quantitative for phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and lyso-phosphatidylcholine (LPC). To determine these components quantitatively, standard curves of authentic compounds were prepared. The peak area of the compound in the mixture was converted into weight percent with the standard curves. Unsaturation was the functional group measured by the detector, therefore, the accuracy of the quantitative results depended upon the degree of unsaturation in the standard compounds. Unsaturation in triglycerides and phospholipids may vary depending upon the season of harvest and the climate of location and production. Two commercial samples of granular soybean lecithin were analyzed. Soybean lecithin was extracted with alcohol and the alcohol-soluble and alcohol-insoluble fractions were analyzed. The results differed both qualitatively and quantitatively.Analyse von Sojaphospholipiden mittels HochdruckflüssigchromatographieUm Phospholipide von Sojabohnen zu analysieren, wurde die HPLC-Methode optimiert. Man verwendet eine Silicagelsäule mit UV-Nachweis bei 210 nm und eine mobile Phase, die aus Hexan, Isopropanol und Wasser besteht. Eine Trennung wird erreicht, indem das Hexan-Isopropanol-Verhältnis konstant gehalten und die Wasser-Konzentration in einem Gradientenelutionsprogramm verändert wird. Die Komponenten in dem HPLC-Chromatogramm wurden durch Vergleich mit den Retentionszeiten authentischer Verbindungen identifiziert. Die Methode ergab für Phosphatidylcholin (PC), Phosphatidylethanolamin (PE), Phosphatidylinositol (PI) und Lysophophatidylcholin (LPC) quantitative Ergebnisse. Um diese Komponenten quantitativ zu bestimmen, wurden Standardkurven mit authentischen Proben aufgenommen. Die Peakflächen der Verbindungen in der Mischung wurden dann mit den Standardkurven in Gewichtsprozente umgerechnet. Die Doppelbindung war die funktionelle Gruppe, die von dem Detektor gemessen wurde. Deshalb hing die Genauigkeit der quantitativen Ergebnisse von dem Grad der Ungesättigtheit der Standardverbindungen ab. Die Ungesättigtheit in Triglyceriden und Phospholipiden kann in Abhängigkeit von Erntesaison und lokalem Klima und Produktion schwanken. Es wurden 2 Handelsproben von granuliertem Sojalezithin analysiert. Das Sojalezithin wurde mit Alkohol extrahiert und die alkohollösliche und alkoholunlösliche Fraktion analysiert. Die Ergebnisse unterschieden sich sowohl qualitativ als auch quantitativ.
    Fett/Lipid 01/1986; 88(1):6-8. DOI:10.1002/lipi.19860880103
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    ABSTRACT: A new diterpene, named rosmariquinone, was isolated from the leaves ofRosmarinus officinalis L. The leaves were first extracted using methanol and, upon further purification, this extract yielded rosmariquinone. Structure elucidation of the antioxidant was done using IR, MS,1H-NMR and13C-NMR.
    Journal of Oil & Fat Industries 12/1984; 62(1):96-98. DOI:10.1007/BF02541500
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    ABSTRACT: A novel antioxidant compound has been isolated and identified from the leaves of theRosmarinus officinalis L. The compound, named rosmaridiphenol, is a diphenolic diterpene. When tested in lard, the antioxidant activity of this compound was superior to BHA. Structural elucidation of rosmaridiphenol was accomplished by infrared spectroscopy (IR), mass spectroscopy (MS),1H-NMR (nuclear magnetic resonance) and13C-NMR spectroscopy.
    Journal of Oil & Fat Industries 05/1984; 61(6):1036-1039. DOI:10.1007/BF02636212
  • Heasook Kim, Chi-Tang Ho, Stephen S. Chang
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    ABSTRACT: Volatile compounds were isolated from 150 lb of commercial oil-free soybean lecithin by vacuum distillation. The isolated volatile compounds were subjected to extensive gas chromatographic fractionation, and the pure fractions thus obtained were identified by mass spectrometry. A total of 79 compounds have been identified. Most of the compounds identified can be postulated as autoxidative decomposition products of unsaturated fatty acids of phospholipids. Isophorone, an acetone-derived compound, was shown to be predominantly responsible for the undesirable flavor of oil-free soybean lecithin. Several nitrogen-containing compounds, e.g., nitriles, acetoxime and 4,5-dimethylisoxazole, were identified as unique volatile compounds from phospholipids.
    Journal of Oil & Fat Industries 01/1984; 61(7):1235-1238. DOI:10.1007/BF02636260